"I've seen confidence," Perez said. "I've seen a guy who knows he belongs. I think that's great. I think that's one of the biggest hurdles here in the big leagues is seeing guys go from the Minor Leagues to the big leagues and you can see the uncertainty in their eyes."
Two years ago, the Marlins told Dominguez -- one of their top prospects at the time -- that the third-base position was his to lose at Spring Training. Miami had selected him with the 12th overall pick in the 2007 First-Year Player Draft.
As a late-season callup in 2011, he played in 17 games, going 11-for-45 (.244) with four doubles and two RBIs.
But in December 2011, Dominguez watched from his home in California as news broke that Miami had signed free agent Jose Reyes and planned to move Hanley Ramirez from shortstop to third base.
As a result, Dominguez began the season at Triple-A New Orleans, blocked by Reyes, a four-time All-Star and 2011's National League batting champion, and Ramirez, a three-time All-Star and the NL batting champion in '09.
When the Marlins struggled to stay within striking distance of a playoff spot, they dealt Dominguez to the Astros for first baseman Carlos Lee in early July. Houston brought him up for four games before the Midsummer Classic, and then he returned to Triple-A Oklahoma City for a month.
From Aug. 30 through the end of the season, Dominguez played pretty much every day, an opportunity he never got with Miami. Over 31 games in 2012, he went 31-for-109 (.284) with five homers, two doubles, two triples, 14 runs and 16 RBIs.
"It was good," Dominguez said. "I think in my mind I'm going to hit. A lot of people don't think so, but I just go out there playing every day. Getting in the groove of things will definitely help you offensively, especially instead of a few at-bats here or there. I'm confident that if I keep working hard, hopefully things will be better."
Current assistant hitting coach Dan Radison worked with Dominguez during his big league stretch, improving his approach heading into games. Dominguez studied how certain pitchers would throw to him and focused on trusting his ability.
What has helped the 23-year-old is being reunited with his Minor League hitting coordinator -- John Mallee -- who is in his first season as the Astros' hitting coach.
According to Mallee, early in Dominguez's professional career he wasn't very strong and relied on his bat speed. The sequence of his swing needed to be tweaked since he had trouble with pitches inside.
During his maturation, Dominguez has learned to use his lower half more to produce more pop off the bat. His fielding has never been a problem, as he's considered above-average with the glove.
Mallee just wishes he had seen Dominguez's Major League debut on Sept. 6, 2011, but it came three months after the Marlins dismissed him and hired Perez in his place.
"When you're a young guy and you're 19- or 20-years-old in Major League camp, and you're supposed to be the next coming and you don't perform, it's hard as a kid to have that confidence," said Mallee, who began working with Dominguez as a 17-year-old. "Now he's been through enough and played enough baseball to know what to expect coming into Spring Training. He's been through it and he's having really good at-bats."
Dominguez entered this spring facing a similar situation as two offseasons ago, considered the favorite for the job at the hot corner.
Astros manager Bo Porter inserted Dominguez into the eighth spot in the lineup for Tuesday afternoon's game against his former team at Roger Dean Stadium, and he hit a two-run homer off Miami ace Ricky Nolasco in his first at-bat. He also walked and singled before getting pinch-run for in the fifth.
Dominguez is now 8-for-21 (.380) this spring with two home runs, three doubles and three RBIs. He has walked four times and struck out just once.
"I think it's a lot easier situation this time than two years ago with the Marlins," Dominguez said. "They say if I have a good Spring Training I'm going to be the third baseman. [It's] more the feeling here, 'We want you to play third. You're going to play third,' so it kind of relaxes you. You can go out and not put pressure on yourself and do what you've got to do."